Residual stress reduction using a low transformation temperature welding consumable with focus on the weld geometry

Low Transformation Temperature (LTT) welding consumables represent an innovative approach to realize compressive residual stress in weld and HAZ. LTT welding consumables use the volume-expanding martensitic phase transformation near room temperature to generate compressive residual stress during cooling. This article focusses on the weld geometry and their influence on residual stress reduction using a LTT welding consumable. For this purpose, layers with a LTT welding consumable were additionally applied to the front sides of conventionally welded longitudinal stiffeners. Different weld geometries of the second weld seam could be realized by varying the welding parameters. These samples were analyzed for geometric parameters, chemical composition, and residual stress. While the chemical composition and martensite start temperature (M_S) was only slightly influenced by parameters changes, a clear influence with regards to residual stress and weld geometry was observed. Depending to the shape of the second weld seam, residual stress reductions of 200 MPa to 500 MPa were achieved using the same LTT welding consumable.